textproduct: Quad Cities

KEY MESSAGES

- Windy weather today will accompany a low chance (20-50%) for gusty thunderstorms as a cold front passes through the area.

- A developing low pressure system over south-central Canada will kick off a warming trend starting on Thursday and bring the chance for numerous (60-80%) showers and a few thunderstorms to the area Thursday night.

SHORT TERM /THROUGH TONIGHT/

Issued at 206 AM CDT Tue May 12 2026

A clipper-type system is making its way southeast through the upper Great Lakes region this morning, with the cold front already reaching western MN by 1 AM. This approaching system is already increasing the surface pressure gradient over our CWA, and combined with a push of Lake Michigan lake breeze, we're already seeing occasional gusts from east to around 25 mph at times.

The first half of today, strong warm advection will take place ahead of the cold front. Though moisture is limited with this advection, clouds and some scattered shower / weak thunderstorm activity is expected to approach our northern counties through mid morning. Much of this may be virga, and despite decent depiction on radar, it is questionable how much of that activity will be capable of wetting surfaces, and eventually measuring 0.01 or more. Farther south, dry weather and plenty of sun will allow for strong heating today.

By Noon and this afternoon, cloud cover will be mainly in the central and southern CWA as the front moves through. The north should begin to clear out, and with strong mixing behind the front, an afternoon high around 80 remains a solid forecast there, while the clouds moving in down south should help limit the highs to the lower 80s there. Winds today will be strong as times, initially from the east/southeast, then south, then by afternoon, southwest and west. Model soundings from Bufkit show much of the wind near the top of the mixed layer around 35kts, which should result in frequent surface gusts this afternoon of 30 to 40 mph. While we are no longer dealing with dry fuels this late in the green-up season, any fire would behave aggressively today in a rather low RH and gusty wind environment, so avoid burning anyway.

Shower and thunderstorms appear rather spotty today, given the limited moisture along the front. As noted from SPC, if dewpoint values could rise the mid 50s (currently forecast to reach near 50), we could see thunderstorms take advantage of steep mid level lapse rates and winds aloft to bring strong storms. This is a low threat, generally under 20% of happening, but if it did, hail could approach 1" and gusts near 60 are possible. This threat, is higher the farther east you go, which is outlined by SPC today.

The front will exit the east/southeastern counties by early evening, and dry weather will confidently move in for the overnight. Models have backed off on strong CAA wind gusts overnight, but non the less, I still expect a gusty northwest wind into the overnight hours, hitting 20-30 mph at times. Lows tonight in the upper 40s to lower 50s are near the mid range of NBM guidance.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 206 AM CDT Tue May 12 2026

Wednesday... Northwest flow aloft and high pressure return to the region Wednesday, allowing for mostly clear skies and seasonable highs in the mid-60s to mid-70s. A strong pressure gradient on the backside of the low pressure over southeast Ontario will support gusty northwest winds up to 30 mph, but the winds are forecasted to subside going into Wednesday night as lows drop into the 40s area- wide.

Thursday-Friday... The next trough moves across the northern Rockies on Thursday, strengthening a mid-latitude cyclone over Saskatchewan. This shoves a longwave ridge over the Midwest as surface flow turns to southeasterly ahead of the approaching cold front. A warming and moistening trend kicks off as highs climb by 3-5 degrees and PWATs increase over 0.5 inch. By Thursday night, a pre-frontal trough and low-to-mid-level isentropic upglide could produce some scattered showers and thunderstorms, but the main surface front stalls out over the Upper Mississippi River Valley as the 500 mb trough negatively tilts over south-central Canada, occluding the mid- latitude cyclone. Due to limited instability and lack of low- level support, the severe threat for these storms is currently low.

On Friday, convergence aloft and dry air advection in the mid-levels will limit PoPs. There is model uncertainty on if the cold front clears the CWA or not which will have an influence on the highs as seen in the LREF probabilities of highs exceeding 80 degrees only being 30-60%. Regardless, this boundary will provide a source of lift heading into the weekend as the next system approaches.

Saturday-Monday... A shortwave in the subtropical jet stream over the Desert Southwest is pulled to the northeast into the Central Plains by a longwave trough over the Pacific Northwest. As a low pressure deepens over western Kansas and Nebraska, the stalled boundary from Friday is expected to be pulled northward as the subtropical trough passes over the region, bringing PoPs back up overnight Saturday. As the trough from the Pacific Northwest enters the Northern Plains on Sunday, a cold front is expected to move into Iowa. Steeper lapse rates should provide enough instability for thunderstorms development with the GFS ensembles showing a 40-70% chance of SBCAPE exceeding 1000 J/kg. Model uncertainty arises again Sunday night into Monday as the ECMWF ensembles have a faster, northely storm system which has the cold front clearing the region while the GFS ensembles have a slower, southerly track that keeps PoPs and thunderstorms chances high into Monday.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1229 PM CDT Tue May 12 2026

VFR conditions will prevail through the TAF period, with main aviation concerns revolving around gusty surface winds and scattered thunderstorms. A cold front will pass through the area this afternoon/evening, with gusty southwest winds ahead of it and west to northwest winds behind. We can see sporadic gusts between 30-35 KTs at times, especially when showers are passing through. Behind the front, winds will die down a little, generally remaining between 10-15 KTs out of the northwest. Ahead of the front, we will also see some scattered showers/storms. Plenty of dry air should keep these largely north of Interstate 80, along with keeping cigs and vis VFR as they pass. Although, some lightning and gusty winds can be seen as these pass. Shower activity should move out of the area between 21-00z. Otherwise, no other sig wx is expected at this time.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.